This Recommendation describes a methodology for the calculation of terrestrial spectrum requirement estimation for International Mobile Telecommunications (IMT). It provides a systematic approach that incorporates service categories (a combination of service type and traffic class)@ service environments (a combination of service usage pattern and teledensity)@ radio environments@ market data analysis and traffic estimation by using these categories and environments@ traffic distribution among radio access technique groups (RATGs)@ required system capacity calculation and resultant spectrum requirement determination. The methodology is applicable to packet switch-based traffic and can accommodate multiple services. It can also accommodate circuit switched emulation traffic using a reservation based concept.